Many adhesive formulations have been described in the art. Among the adhesives described are hot melt adhesives. Known adhesives contain copolymers such as hydrogenated butadiene-styrene copolymers, modifying agents for these copolymers, plasticizers and other additives. There is a continuing need in the art to improve the holding power of pressure sensitive adhesives, and in particular those employed as hot melts. These adhesives have a wide range of application varying from masking tapes and labels to construction materials and the automotive industry. Increasing the service temperature or adhesive strength (holding power) for a particular type of adhesive generally enlarges the adhesive's application area. During the past several years conjugated diene/monovinyl aromatic block copolymers have been used as the basic ingredient in some hot melt adhesive compositions. To increase the use or service temperature of these and other similar compositions, polymers such as polyphenylene oxide known to have good thermal stability, have been added. U.S. Pat. No. 4,104,323 describes a hot melt adhesive based on a conjugated diene block copolymer, having therein polyphenylene oxide resins to give improved high temperature properties. Also incorporated therein are materials referred to as tackifiers (modifying agents) that are compatible with either the polyconjugated diene portion of the base copolymer or with the polyvinylaromatic portion of the base copolymer.